JP2002303873A - Active matrix type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an opening ratio. SOLUTION: In an active matrix type liquid crystal display device which is provided with transparent substrates facing each other through a liquid crystal layer which is provided with an electrode for display and a reference electrode in an area corresponding to a unit pixel on the side of the liquid crystal layer and which varies light transmittance of the liquid crystal layer by the electric field having a component parallel to the transparent substrate surfaces generated between the electrode for display supplied with a video signal from a video signal line through a switching element to be turned on by a scanning signal supplied from a scanning signal line and the reference electrode impressed with a reference voltage, the reference electrode is placed between the unit pixel and another unit pixel adjacent to that unit pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an active matrix type liquid crystal display device, and more particularly to an active matrix type liquid crystal display device called a horizontal electric field type.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display panel called a horizontal electric field type is provided on a surface of an area corresponding to a unit pixel on one or both liquid crystal sides of a transparent substrate arranged to face each other via a liquid crystal. , A display electrode and a reference electrode are provided, and light transmitted through the liquid crystal is modulated by an electric field generated between the display electrode and the reference electrode in parallel with the transparent substrate surface. .

[0003] Such a liquid crystal display panel can recognize a clear image even when viewed from a large angle field of view with respect to its display surface, and has come to be known as having a so-called wide angle field of view.

A liquid crystal display panel having such a configuration is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-50524.
No. 7, JP-B-63-21907, and JP-A-6-160878.

[0005]

In each of these documents, a plurality of scanning signal lines arranged in parallel and a plurality of video signals arranged in parallel with each scanning signal line are described. Each region surrounded by is defined as a pixel region, and the display electrode and the reference electrode are arranged inside the pixel region.

However, in the active matrix type liquid crystal display device, the so-called aperture ratio cannot be sufficiently secured because the light transmittance is controlled by the behavior of the liquid crystal layer between the display electrode and the reference electrode. It has been pointed out.

The present invention has been made based on such circumstances, and an object of the present invention is to provide an active matrix type liquid crystal display device having an improved aperture ratio of a pixel region.

[0008]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

Means 1. According to the present invention, for example, a transparent substrate is arranged to face each other via a liquid crystal layer, and a display electrode and a reference electrode are provided in a region corresponding to a unit pixel on the liquid crystal layer side, and scanning from a scanning signal line is performed. The display electrode, to which a video signal is supplied from a video signal line via a switching element that is turned on by the supply of a signal, and a transparent substrate surface that is generated between the reference electrode to which a reference voltage is applied. In an active matrix liquid crystal display device in which the light transmittance of the liquid crystal layer is changed by an electric field having a component, a reference electrode is arranged between the unit pixel and another unit pixel adjacent to the unit pixel. It is a feature.

Means 2. According to the present invention, for example, on the premise of the configuration of the means 1, the unit pixel and another unit pixel adjacent to the unit pixel are two adjacent pixels among three pixels forming one pixel for color display. It is characterized by the following.

Means 3. The present invention is characterized in that, for example, on the premise of the configuration of the means 1, the unit pixel and another unit pixel adjacent to the unit pixel are displayed by a video signal from a different video signal line. .

Means 4. The present invention is, for example, characterized in that the display electrode and the reference electrode have a band shape on the premise of the configuration of the means 1.

Means 5 The present invention is characterized in that, for example, on the premise of the configuration of the means 1, the unit pixel has a length in a direction in which the reference electrode extends in a direction perpendicular to the reference electrode.

Means 6. The present invention is characterized in that, for example, on the premise of the configuration of the means 1, the display electrode is formed so as to divide the pixel into two.

Means 7 The present invention is characterized in that, for example, on the premise of the configuration of the means 1, the reference electrode also serves as a reference signal line.

Means 8 According to the present invention, for example, a transparent substrate is arranged to face each other via a liquid crystal layer, and a display electrode and a reference electrode are provided in a region corresponding to a unit pixel on the liquid crystal layer side, and scanning from a scanning signal line is performed. The display electrode, to which a video signal is supplied from a video signal line via a switching element that is turned on by the supply of a signal, and a transparent substrate surface that is generated between the reference electrode to which a reference voltage is applied. An active matrix type liquid crystal display device in which the light transmittance of the liquid crystal layer is changed by an electric field having a component has a reference electrode shared by adjacent unit pixels.

Means 9 According to the present invention, for example, on the premise of the configuration of the means 8, each of the unit pixels adjacent to each other includes two adjacent pixels among three pixels constituting one pixel for color display.
It is characterized by being a pixel.

Means 10. The present invention is characterized in that, on the premise of the configuration of the means 8, for example, the adjacent unit pixels are displayed by video signals from different video signal lines.

Means 11 The present invention is, for example, characterized in that the display electrode and the reference electrode have a band shape on the premise of the configuration of the means 8.

Means 12. The present invention is, for example, characterized in that the length of the unit pixel in the extending direction of the reference electrode is longer than the length of the unit pixel in a direction orthogonal to the reference electrode, based on the configuration of the means 8.

Means 13. The present invention is characterized in that, for example, on the premise of the configuration of the means 8, the display electrode is formed so as to divide the pixel into two.

Means 14. The present invention is characterized in that, for example, on the premise of the configuration of the means 8, the reference electrode also serves as a reference signal line.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the active matrix type display device according to the present invention will be described.

Embodiment 1 FIG. FIG. 9 is a schematic diagram showing a horizontal electric field type liquid crystal display panel and its peripheral circuits.

In FIG. 1, the liquid crystal display panel 1 has a transparent substrate 1A and a transparent substrate 1B as an envelope, and a liquid crystal layer is interposed between them. On the surface of the liquid crystal layer of the transparent substrate 1A, which is a so-called lower substrate, a scanning signal line 2 and a reference signal line 4 extending in the x direction in the figure and juxtaposed in the y direction are formed. The scanning signal line 2 and the reference signal line 4 are arranged closer to a certain scanning signal line 2 in the −y direction, and −y to the reference signal line 2.
The scanning signal lines 2 are disposed so as to be largely separated in the direction, and the reference signal lines 4 are disposed adjacent to the scanning signal lines 2 in the −y direction. Further, the video signal lines 3 are formed so as to extend in the y direction and be juxtaposed in the x direction insulated from the signal lines 2 and 4.

A rectangular area surrounded by the scanning signal line 2, the reference signal line 4, and the video signal line 3 becomes a pixel area, and these pixel areas are arranged in a matrix to constitute a display section. It has become. A display electrode is formed in each pixel region, and a thin film transistor TFT and a storage capacitor Cstg are arranged in a part of the periphery of the pixel region (neither of these is shown but will be described later in detail). Described).

The liquid crystal display panel 1 is provided with a vertical scanning circuit 5 and a video signal driving circuit 6 as its external circuits.
Are sequentially supplied with a scanning signal (voltage), and the video signal driving circuit 6
Is supplied with a video signal (voltage).

The vertical scanning circuit 5 and the video signal driving circuit 6 are supplied with power from a liquid crystal driving power supply circuit 7 and transmit image information from the CPU 8 to the controller 9.
Thus, the display data and the control signal are divided and input. Here, the display data is input via the image memory 410 in this embodiment. The function of the image memory 410 will be described later in detail.

The voltage applied to the reference signal line 4 is also supplied from the liquid crystal drive power supply circuit 7. In this embodiment, an AC voltage is used as the voltage applied to the reference signal line 4 for the purpose of reducing the withstand voltage of the video signal drive circuit 6.

FIG. 1 is a plan view showing a detailed configuration of one pixel region (corresponding to a portion surrounded by a dotted line in FIG. 9) in the liquid crystal display panel 1. As shown in FIG.

FIG. 2 is a sectional view taken along the line II-II, FIG. 3 is a sectional view taken along the line III-III, and FIG.
FIG. 4 is a cross-sectional view taken along line -IV.

First, on the surface of the transparent substrate 1A on the liquid crystal layer side,
The scanning signal line 2 extending in the x direction is formed of, for example, Al. A reference signal line 4 is formed in the vicinity of the scanning signal line 2 on the y direction side so as to extend in the x direction. This reference signal line 4 is also formed of, for example, Al. Here, as described above, a pixel region is formed by a region surrounded by the scanning signal line 2, the reference signal line 4, and a video signal line 3 described later. Here, in this embodiment, the pixel region is formed such that the side on the adjacent video signal line side is smaller than the side on the scanning signal line side,
It is a so-called horizontal stripe type.

In this pixel region, the reference signal line 4 itself is used as a reference electrode 14, and another reference electrode 14 is formed adjacent to the scanning signal line 2. Each of these reference electrodes 14 is a video signal line 3 (right side in the drawing) of one of the video signal lines 3 described later.
, And electrically connected to each other by a conductor layer 14A formed simultaneously with the reference electrode 14.

Thus, each reference electrode 14 extends in a direction parallel to the scanning signal line 2, in other words, a band-like shape extending in a direction orthogonal to the video signal line 3 described later. Will be configured.

On the surface of the transparent substrate 1A on which the scanning signal lines 2 and the like are formed, an insulating film made of, for example, a silicon nitride film covers the scanning signal lines 2, the reference signal lines 4, and the reference electrodes 14. 11 (see FIGS. 2, 3, and 4). The insulating film 11 serves as an interlayer insulating film between the scanning signal line 2 and the reference signal line 4 for a video signal line 3 to be described later, and as a gate oxide film for a region for forming a thin film transistor TFT, and a region for forming a storage capacitor Cstg. Function as a dielectric film.

On the surface of the insulating film 11, first, a semiconductor layer 12 is formed in a region where the thin film transistor TFT is formed. The semiconductor layer 12 is made of, for example, amorphous Si, and is formed on the scanning signal line 2 so as to overlap with a portion close to the video signal line 3 (the left video signal line in the drawing). Thereby, a part of the scanning signal line 2 is configured to also serve as the gate electrode of the thin film transistor TFT.

Further, on the surface of the insulating film 11, a video signal line 3 extending adjacent in the y direction is formed by, for example, a sequentially laminated body of Cr and Al. The video signal line 3 is partially extended so that the semiconductor layer 1
The drain electrode 3A formed on a part of the surface of the second electrode 2 is integrally formed.

Further, a display electrode 15 is formed on the surface of the insulating film 11 in the pixel region. The display electrode 15 is formed so as to divide the pixel area into two, for example. That is, one end of the display electrode 15 is formed integrally with the source electrode 15A of the thin film transistor TFT,
After extending in the + y direction in the figure, it extends in the + x direction. Accordingly, the display electrode 15 is configured to extend in a direction parallel to the scanning signal line 2, in other words, to have a strip shape extending in a direction orthogonal to the video signal line 3. become.

In this case, the tip of the display electrode 15 has a T-shaped portion extending along the conductive layer 14A connecting the reference electrodes 14 to each other, and this portion is a dielectric. A storage capacitor Cstg including the insulating film 11 as a body film is formed. This storage capacity Cstg is
As a result, for example, when the thin film transistor TFT is turned off, the effect is obtained that video information is accumulated in the display electrode 15 for a long time.

The drain electrode 3A and the source electrode 15A of the thin-film transistor TFT and the semiconductor layer 1
The interface of No. 1 is doped with phosphorus (P) to form a high concentration layer, thereby achieving ohmic contact with each of the electrodes. In this case, after the high-concentration layer is formed over the entire surface of the semiconductor layer 11, the electrodes are formed, and the high-concentration layers other than the electrode formation region are etched using these electrodes as a mask to achieve the above-described configuration. can do.

Then, as described above, the thin film transistor TF
On the upper surface of the insulating film 11 on which the T, the video signal line 3 and the storage capacitor Cstg are formed, the protective film 16 made of, for example, a silicon nitride film is covered with the thin film transistor TFT or the like.
(See FIGS. 2, 3, and 4), and an alignment film 17 is formed on the upper surface of the protective film 16 to constitute a so-called lower substrate of the liquid crystal display panel 1. Note that a polarizing plate 18 is disposed on the surface of the lower substrate opposite to the liquid crystal side.

As shown by a broken line in FIG. 1, a light-shielding film 300 is formed in a portion of the transparent substrate 1B serving as a so-called upper substrate on the liquid crystal side by opening most of the central portion excluding the peripheral portion of the pixel region. Have been. The light-shielding film 300 is formed for the purpose of preventing the irradiation of extraneous light to the thin film transistor TFT, thereby preventing the characteristic thereof from deteriorating, and improving the contrast in display.
The light shielding film 300 is made of, for example, an organic resin in which a black pigment is dispersed.

FIG. 2 shows a cross section of the transparent substrate 1B on which the light shielding film 300 is formed, and a color filter 25 is formed on the opening of the light shielding film 300 so as to cover the opening. Then, a flat film 27 is formed so as to cover the color filter 25 and the light shielding film 300.
An alignment film 28 is formed on the surface of the liquid crystal layer 7 on the liquid crystal layer side.

Here, the color filter 25 corresponds to FIG.
As shown in the figure, for example, a red (R) filter, a green (G) filter, and a blue (B) filter are arranged in three pixel regions adjacent to each other along the extension of the video signal line 3 from the top in the figure. Thus, the three pixel areas constitute one pixel area for color display.

A polarizing plate 29 is disposed on the surface of the upper substrate formed in this manner, which is opposite to the liquid crystal layer side.

In FIG. 2, when a voltage is applied between the reference electrode 14 and the display electrode 15, an electric field E is generated in the liquid crystal layer LC in parallel with each surface of the transparent substrates 1A and 1B. It indicates that. As described above, this is the reason why it is called a horizontal electric field method.

Here, the relationship between the alignment film 17 formed on the transparent substrate 1A and the polarizing plate 18 and the relationship between the alignment film 28 formed on the transparent substrate 1B and the polarizing plate 29 will be described with reference to FIG.

With respect to the direction 207 of the electric field applied between the display electrode 15 and the reference electrode 14, the alignment films 17 and 28
Of the rubbing direction 208 is 75 degrees. The angle φP of one of the polarizing plates 18 in the polarization transmission axis direction 209 is equal to φLC. The polarization transmission axis direction of the other polarizing plate 29 is zero.
9 is orthogonal. As the liquid crystal layer LC, a nematic liquid crystal composition having a positive dielectric anisotropy Δε, a value of 7.3 (1 kHz) and a refractive index anisotropy Δn of 0.073 (589 nm, 20 ° C.). Is used.

With this configuration, by generating an electric field parallel to the transparent substrate 1A in the liquid crystal layer LC, light transmitted through the liquid crystal layer LC can be modulated. In particular, a so-called normally black mode in which black display is performed when no electric field is applied and white display is performed when an electric field is applied can be provided.

In the configuration described above, each of the three pixels constituting one pixel for color display is different from the conventional one.
Those adjacent to each other along the extending direction of the video signal line 3 are assigned. On the other hand, the display data from the controller 9 shown in FIG. 9 is conventionally configured such that the R, G, and B pixel signals are transmitted in parallel to adjacent video signal lines at a frequency corresponding to, for example, 60 Hz. Has become.

For this reason, in this embodiment, as shown in FIG. 9, an image memory 410 is particularly provided.
The pixel signals R, G, and B from the CPU 8 are temporarily stored in the CPU 10, and the respective signals are sequentially supplied to one video signal line 3 by the controller 9.

FIG. 7 is a diagram showing the drive timing at this time. In the figure, Vd is a pixel signal supplied to one video signal line 3, Vg ₁ , Vg ₂ , Vg ₃ are gate signals supplied to each of three pixels constituting one pixel for color display, Vr , Vg, and Vb are R, G,
4 illustrates a pixel signal supplied to each pixel of B.

The present invention is not limited to the provision of the image memory 410, but an interface is provided between the CPU 8 and the controller 9 so that the pixel signal from the CPU 8 is changed by the interface as described above. Needless to say, this may be done.

According to the liquid crystal display panel of the embodiment described above, each unit pixel area is configured to be smaller on the side closer to the video signal line 3 than on the side closer to the scanning signal line 2. . That is, a horizontal stripe structure is used instead of the conventional vertical stripe structure.

For this reason, in the unit pixel region extending in the horizontal direction, the region where the electric field from the video signal line 3 goes around is on both sides of the unit pixel region. It becomes a small area, and so-called vertical smear can be suppressed much more than before.

The display electrode 15 and the reference electrode 14
Are formed in a strip shape extending in the direction orthogonal to the video signal line 3, respectively, so that the electric field from the video signal line 3 wraps around the display electrode 15 or the reference electrode 14 when the electric field is terminated. Since the electric field is perpendicular to the electric field between the display electrode 15 and the reference electrode 14 involved in the actual display, the electric field does not adversely affect the actual display.

FIG. 8 shows the display electrode 15 or the reference electrode 14 of the video signal line 3 in the pixel region.
The wraparound of the electric fields E ₁ and E ₂ (FIG. 7A) when the termination is made to the video signal line 3 in the conventional pixel region.
FIG. 9 is a diagram in comparison with the wraparound E ₁ and E ₂ of the electric field when terminating to the display electrode 15 or the reference electrode 14 (FIG. 9B).

In the above-described embodiment, in each of the pixel regions, the side on the side of the video signal line adjacent thereto is smaller than the side on the side of the scanning signal line, and the display electrode and the reference electrode are respectively connected to the video signal line. And a belt-like shape extending in a direction perpendicular to the direction.

However, the display electrodes and the reference electrodes may extend in the directions parallel to the video signal lines, respectively, only by making the adjacent video signal line side smaller than the scanning signal line side. Needless to say.

Further, only the display electrode and the reference electrode each have a strip shape extending in a direction perpendicular to the video signal line, and the pixel region is formed by scanning the adjacent side of the video signal line with the scanning signal line. Needless to say, the side may be larger than the side.

In any case, the effect of suppressing the generation of vertical smear can be obtained as compared with the conventional case.

Further, it is needless to say that the present invention is not limited to a color display but can be applied to a monochrome display.

Embodiment 2 FIG. FIG. 10 is a plan view showing another embodiment of the active matrix display panel according to the present invention.

In the figure, each pixel region arranged along the extending direction of the video signal line 3 is responsible for, for example, each color of R, G, B, R,. The configuration is the same as that of Example 1. However, among the three pixels constituting one pixel for color display, two adjacent pixels share one scanning signal line, and the two adjacent pixels are displayed by video signals from different video signal lines 3. Is different.

That is, the above R, G, B, R, G, B,
In the arrangement of R, G,..., Two pixels (R, G), (B, R), (G, B), (R, G),.
Scanning signal line 2 is arranged between each of
In each of the pixels, the upper pixel is displayed by the video signal from the video signal line 3 located on the left side in the figure, and the lower pixel is displayed by the video signal from the video signal line 3 located on the right side in the figure. It has become so.

In the display panel configured as described above, the number of the scanning signal lines 2 can be reduced, and accordingly, the aperture ratio can be improved as the area of the pixel region increases.

In this case, after storing two lines of pixel data among the pixel data from the CPU 8 shown in FIG. 9 in the image memory 410, every two-thirds of the unit selection time of the vertical stripe arrangement, The scanning signal line 2 in units of two pixels
And driving is performed by sequentially applying pixel data to the video signal line 3.

That is, as shown in FIG.
The pixels arranged in the extending direction of the line 3 are sequentially denoted by R₁,
G₁, B₁, R₂, G₂, B₂, R₃, ...
R₁And G ₁Scanning signal line 2 between₁, B₁And R₂Between
Scan signal line 2₂, And G₂And B₂Scan signal between
Line 2₃Sequentially include the scanning signals Vg, respectively.₁, Vg₂,
Vg₃Is applied. Selection of the scanning signal line 2 by this application
Selection is equivalent to selecting one line in a vertical stripe arrangement
Every 2/3 hours of the unit scanning time.

At this time, two adjacent video signal lines 3₁,
3₂From the video signal Vd ₁, Vd₂Is supplied
It is supposed to be. Each of these video signals Vd₁, Vd
₂Is the scanning signal Vg₁, Vg₂, Vg₃Synchronized with the unit
It is applied every 2/3 of the scanning time.
You. As a result, R₁, G₁, B₁, R₂, G₂, B₂of
The waveform of the potential of each pixel is as shown in FIG.

From this, it can be seen that even in the configuration of the horizontal stripe arrangement, while writing two lines in the vertical stripe arrangement, writing can be performed for the pixels corresponding to the two lines.

Therefore, in this embodiment, when compared with the structure of the vertical stripe arrangement, the frequency of the scanning signal is set to 1.5.
The write characteristics of the thin film transistor TFT can be improved.

Embodiment 3 FIG. FIG. 12 is a plan view showing another embodiment of the active matrix type liquid crystal display panel according to the present invention. FIG. 13 is a sectional view taken along line XIII-XIII in FIG.

In FIG. 12, each pixel region arranged along the extending direction of the video signal line 3 is responsible for, for example, each color of R, G, B, R,. The configuration is the same as that of Example 1. However, among the three pixels constituting one pixel for color display, two adjacent pixels share one scanning signal line, the remaining one pixel occupies one scanning signal line, and each pixel is different. The difference is that the display is made by the video signal from the video signal line 3.

In this case, the scanning signal line to be shared and the scanning signal line to be occupied are connected to each other in an area other than the display area, for example, so that the same scanning signal is supplied.

A video signal line 3 for supplying a video signal to each pixel
Is assigned to one on the left and two on the right in the figure.
Of the two video signal lines 3, the video signal line 3 located on the outside is the video signal line 3 located on the inside and the thin film transistor TFT of the pixel in charge through the interlayer insulating film 11.
Is connected to the drain electrode 3A.

The liquid crystal display panel thus configured has
Display is performed by the same driving method as that of the vertical stripe arrangement. For this reason, the image memory 410 described above
Alternatively, there is an effect that display can be performed without any need for an interface or the like.

[0077]

As is apparent from the above description,
According to the liquid crystal display device of the present invention, the aperture ratio can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a pixel region showing one embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line VI-VI of FIG.

FIG. 5 is a layout view of a color filter showing one embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is an explanatory diagram showing a relationship between an alignment film and a polarizing plate used in the liquid crystal display device according to the present invention.

FIG. 7 is a timing chart showing one embodiment of a method for driving a liquid crystal display device according to the present invention.

FIG. 8 is an explanatory diagram showing an effect of the liquid crystal display device according to the present invention.

FIG. 9 is a schematic diagram showing one embodiment of a liquid crystal display device and peripheral circuits according to the present invention.

FIG. 10 is a plan view of a pixel region showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 11 is a timing chart showing one embodiment of a driving method of the liquid crystal display device shown in FIG.

FIG. 12 is a plan view of a pixel region showing another embodiment of the liquid crystal display device according to the present invention.

13 is a sectional view taken along line XIII-XIII in FIG.

[Explanation of symbols]

2 ... scanning signal line, 3 ... video signal line, 4 ... reference signal line, 14 ... reference electrode, 15 ... display electrode, TFT ...
... Thin film transistor, Cstg...

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kazuhiro Ogawa 3300 Hayano Mobara-shi, Chiba Electronic Device Division, Hitachi, Ltd. (72) Inventor Keiichiro Ashizawa 3300 Hayano Mobara-shi, Chiba Electronic Device Business Hitachi, Ltd. In-house (72) Inventor Minoru Hoshino 3300 Hayano Mobara-shi, Chiba F-term (Reference) 2H092 GA14 GA32 GA61 JA24 JA34 JA37 JA41 JB05 JB13 JB51 JB57 JB58 JB61 MA18 NA07 PA06 PA08

Claims (14)

[Claims] A transparent substrate is disposed opposite to each other with a liquid crystal layer interposed therebetween, and a display electrode and a reference electrode are provided in a region corresponding to a unit pixel on the liquid crystal layer side, and a scanning signal from a scanning signal line is provided. A component parallel to the transparent substrate surface generated between the display electrode to which a video signal is supplied from a video signal line via a switching element that is turned on by the supply of the reference electrode and a reference electrode to which a reference voltage is applied. An active matrix type liquid crystal display device in which the light transmittance of the liquid crystal layer is changed by an electric field, wherein a reference electrode is disposed between the unit pixel and another unit pixel adjacent to the unit pixel. Active matrix type liquid crystal display device. 2. The unit pixel according to claim 1, wherein the unit pixel and another unit pixel adjacent to the unit pixel are two adjacent pixels among three pixels constituting one pixel for color display. Active matrix liquid crystal display. 3. The active matrix liquid crystal display device according to claim 1, wherein the unit pixel and another unit pixel adjacent to the unit pixel are displayed by a video signal from a different video signal line. 4. The active matrix type liquid crystal display device according to claim 1, wherein the display electrode and the reference electrode have a band shape. 5. The active matrix liquid crystal display device according to claim 1, wherein a length of the unit pixel in a direction in which the reference electrode extends is longer than a length in a direction orthogonal to the reference electrode. 6. The active matrix liquid crystal display device according to claim 1, wherein the display electrode is formed so as to divide the pixel into two. 7. The active matrix type liquid crystal display device according to claim 1, wherein said reference electrode also serves as a reference signal line. 8. Transparent substrates are arranged to face each other with a liquid crystal layer interposed therebetween. A display electrode and a reference electrode are provided in a region corresponding to a unit pixel on the liquid crystal layer side, and a scanning signal from a scanning signal line is provided. A component parallel to the transparent substrate surface generated between the display electrode to which a video signal is supplied from a video signal line via a switching element that is turned on by the supply of the reference electrode and a reference electrode to which a reference voltage is applied. An active matrix type liquid crystal display device for changing the light transmittance of the liquid crystal layer by an electric field having a reference electrode shared by adjacent unit pixels. 9. The active matrix type liquid crystal display device according to claim 8, wherein the adjacent unit pixels are two adjacent pixels among three pixels forming one pixel for color display. 10. The active matrix type liquid crystal display device according to claim 8, wherein said adjacent unit pixels are displayed by video signals from different video signal lines. 11. The active matrix type liquid crystal display device according to claim 8, wherein the display electrode and the reference electrode have a band shape. 12. The active matrix liquid crystal display device according to claim 8, wherein the unit pixel has a length in a direction in which the reference electrode extends in a direction perpendicular to the reference electrode. 13. The active matrix type liquid crystal display device according to claim 8, wherein the display electrode is formed so as to divide the pixel into two. 14. The active matrix type liquid crystal display device according to claim 8, wherein said reference electrode also serves as a reference signal line.